<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      const user = {
        username: "jack",
        age: 20,
        // size:200
      };
      Object.defineProperties(user, {
        size: {
          value: 200,
          writable: true,
          enumerable: true,
          configurable: true,
        },
        hobby: {
          value: ["css", "html"],
        },
      });
      console.log(user);
      console.log(Object.getOwnPropertyDescriptors(user));
    </script>
  </body>
</html>
